Apparatus for disposing of dust



Nov. 10, 1942.

H. J. WILLMOTT APPARATUS FOR bISPOSING OF DUST 2 Sheets-Shet 1 FiledJan. 4, 1941 Nov. 10, 1942. H, J w L 2,301,351

APPARATUS FOR DISPOSING OF DUST Filed Jan. 4, 1941 ZSheetS-Sheet 2Patented Nov. 10, 1942 a srr APPARATUS FOR DISPOSING OF DUST ApplicationJanuary 4, 1941-, Serial No. 373,153

1 Claim. (01. mm)

This invention relates to apparatus for disposing of the dust whichresults from theoperation of abrading machines and is herein illustratedand described as embodied in-a shoe repair machine having a dustcollecting system associated with the various bufling tools with whichsuch machines are usually equipped. The purpose of the dust collectingsystem is to remove dustv from the locality of operation by a suctiondraft and then to separate the dust from the air in which it has beenentrained and to deliver the dustfree air back into. the room.

It is an object of the present invention to provide, for the purposereferred to above, an improved dust collecting system which issufiiciently J compact to be housed within. the frame of a. shoe repairmachine and which requires a minimum of power for its operation. Withthis object in view, the illustrated machine, is. provided with a dusthood partially surrounding an abraiding tool and with a dust settlingchamberbelow the hood, with the hood opening into the chamber andaffording an air passage which atall localities has a greatercross-sectional area than the. cross-sectional area of the tool. Therelatively large passage enables the incoming air to travel atrelatively low speed and thereby avoids stirring up dust which hassettled within the chamber while at the same time requiring a minimum ofpower to draw the air through the passage. As illustrated herein, theseveral bufiing tools of the machine are provided with individual dusthoods which open into a common settling chamber through passages ofrelatively large cross-sectional area. These hoods, it will be noted,constitute in effect upward extensions of the settling chamber. In theupper portion of the chamber and separated from the inlet passage by abafi'le is an outlet conduit which leads to the intake of a fan whilethe exhaust from this fan leads to a filter bag. The air leaving thesettling chamber by the way of said outlet conduit is relatively free ofdust andthe small amount of dust'still entrained therein issubstantially all removed as it passes through the filter bag.

These and other features of the invention will be described as embodiedin an illustrative machine and pointed out in the appended claim.

Referring now to the accompanying. drawings,

Fig. 1 is a front elevation of a shoe repair machine provided with animproved dust collecting system;

Fig. 2 is an end elevation of the machine shown in Fig. 1 looking in thedirection of the arrow II;

Fig. 3 is a verticalsection ofthe machine taken on the line III-III ofFig. 1;

Fig. .4 is a vertical section taken on theli-ne IV'IV of Fig. l; and

Fig. 5 is an enlargement of a portion of Fi ,4 showing the dust-hood.

The supporting structure of the illustrated machine consists of threeupright frame members l9, l2 and I4 connectedby fourhorizontal membersl6, l8; 26) and 22. which extend lengthwise. Carried by and above thisframe structure is a shelf 24.

Theoperating instrumentalities of the machine include a plurality ofbrushes and other cleaning tools 26 for cleaning and polishing shoes,these tools 26 being carried upon a horizontal shaft 23 which, isjournaled in bearings 30 supported by the frame structureof the machine.The bearings 30 are carried by supports 29which are adjustable up anddown in split sockets provided with clamping bolts 3| (Fig. 2) to securethe supports in desired positions of heightwise adjustment. The tools 26are backed by a; sheet metal guard 33. Other operating instrumentalitiescomprise three heel bufling wheels 32 and: a bottom bufiing roll 34 allmounted upon a shaft 35 which is journaled in bearings 38 supported bythe frame structure of the machine. The bearings 38 are carried bysupports 31 which are slidable up and down in split sockets providedwith clamping bolts 39 (Fig. 3) to secure the supports in desiredpositions of heightwise adjustment. As illustrated herein, the shafts 23and 36 are at about the same level and are arranged above the forwardportion of the frame structure at a convenient height for the operator.Associated with each of the heel bufiing wheels 32 is an individual dusthood it and associated with the bottom scouring roll 34 is a dust hood.42'. All of, these dust hoods open downwardly into a common settlingchamber 44 (Fig. 4) which occupies the space between the upright framemembers l2 and I i-within the frame structure of the machine. Thesettling chamber 44 issupported by'metal straps. 46 (Figs. 1 and 4)secured around: the

longitudinal framemembers 22 and I6. Air is withdrawn from the chamber44 through an outlet conduit' 48-by a fan 59, the discharge end of saidfanbeing connected to a conduit 52 which leads to a filter 540i asuitable fabric for screening fine dust. This filter is convenientlyrectangular in cross section and hangs from a metal top plate 55 whichis supported by straps 58 secured around the longitudinal frame members22 and I8. The lower end of the filter is secured to a rectangularbottom plate 55 (Fig. 1) the central portion of which is cut out,leaving only a continuous rim around the four sides. The front portionof this plate is supported by two tie rods 51 secured at their upperends to the top plate 56 and extending downwardly within the filter.

.The rear portion of the plate 55 is supported by illustrated in Figs. 4and 5. As shown in thosefigures, the hood 4!] has a rear wall 60 whichextends upwardly from the top of the chamber 44 and forwardly over thebufiing wheel 32.

hood 40 is provided also with a pair of parallel 4 side walls 62 whichare spaced closely to the respective faces of the wheel 32, and with aforwardly and laterally flaring throat 64 below the wheel. The sidewalls 62 are notched to clear the shaft 36. A hinge 65 enables the upperportion of the hood to be swung upwardly and backwardly when access tothe wheel 32 is desired. The rear wall .66 together withthe side walls62 and the throat 64 define a passageway which extends downwardly intothe chamber 44 and all portions of this passageway have across-sectionalarea which is greater than that of the cross-sectional area of thewheel. Furthermore, the Width of this air passage measured forwardly andrearwardly is greater than the diameter of the wheel.

A further feature of the hood structure consists in the provision of apair of interior vanes 66 and 68, and also two partitions l0 and 12. Thevanes 66 and 68 are located at the rear of the wheel 32, their forwardportions being spaced closely to the periphery of the wheel and almosttangent thereto. The vane 66 has a forward portion 61, and the vane 68has a forward portion 69. Each of these forward portions extendsupwardly and rearwardly in a straight line, or rather a plane, which isperpendicular to a radius from its forward edge to the axis of the toolshaft 36, said forward edge being as close to the tool 32 as clearancepermits. The remaining portion of each vane continues from the forwardportion in a smooth curve which extends first upwardly and rearwardly,then rearwardly, and then rearwardly and downwardly. The rearwardly anddownwardly extending portion of the lower vane 66 is considerably longerthan that of the upper vane 68. It will be noted that the vanes 66 and68 do not extend all the way to the rear wall 60, but leave amplepassageways for the flow of air adjacent to the rear wall. The partition10, however, which is curved similarly to the vanes 66 and 68, begins asclosely to the tool 32 as clearance permits and extends all the way tothe rear wall f to close the upper portion of the dust hood. The

partition 12 begins at the forward edge of the partition 10 and extendsin an are about the tool 32 to the forward edge of the rear wall 6!],being spaced as close to the periphery of the tool 32 as clearancepermits. The partitions 10 and I2 and the rear wall 66 thus completelyenclose a dead air space 14. Functionally, therefore, the partitions 10and 12 may be regarded as constituting the upper portion of the rearwall of the dust hood, the rear wall 66 being continued over them merelyfor considerations of construction and appearance.

The hood 42 while differing in dimensions from 78,

vertical baffle I6.

the hoods 40 is similar in construction to those hoods, and is providedwith similar vanes and partitions.

The several dust hoods, by reason of the construction above described,can operate efficiently with a minimum of suction induced by the fan 50within the chamber 44-. Referring to Fig. 5, it is evident that therotation of the tool will set up a current of air leading into theopening of the throat 64, and that this current will draw additional airwith it over the lip of the throat. Much of the dust resulting from theoperation of the tool will be impelled, by the rotation of the toolitself, into the throat opening; and substantially all of the remainingdust will be drawn in by the entering air. Most of this dust continuesits downward movement through the hood. A portion of it, however, isentrained in the peripheral air current set up by the rotation of thetool 32 or becomes embedded in the abrasive material of the wheel. Themajor portion of the peripheral current is deflected from the tool bythe forward portionfi'l of the vane 66, and is directed downwardly, witha minimum of disturbance, by the curved portion of the vane. A smallamount of entrained and embedded dust, however, may pass through theclearance space between the forward portion 61 and the periphery of thetool. The stationary straight portion 61, however, being close to theperiphery of the tool, will exert a powerful frictional effect upon themoving film of air, giving rise to turbulence within the film thatexerts a scouring action tending to remove any dust clinging to orembedded in the abrasive material of the tool. Moreover, the gradualflaring of the space between the vane and the tool produces the effectof an expansion nozzle; the thin peripheral film of air with entraineddust expands until most of it is'rem'oved from the direct influence ofthe rotating tool. The vane 68, with its forward portion 69, willoperate in the same way upon the small amount of dust that passes thevane 66; and the partition 10 will direct downwardly the almostnegligible amount of dust which passes the vane 68. As a furtherprecaution against even a small amount of dust escaping from under theforward end of the rear wall 60, the partition 12, extending over a wideare close 'to the periphery of the tool, exerts sufiicient friction toblock effectively the passage of air between it and the tool. It istherefore evident that the hood 40 V by reason of its construction, andwithout depending upon suction, is capable of gathering the dustgenerated by the operation of the tool, directing this dust downwardlyin a quiet stream,

' and preventing any of it from escaping over the top of the tool.-

The. interior ofthe upper portion of the settling chamber 44 is dividedlongitudinally by a The lower ends of the rear Walls 69 of the variousdust hoods are continuous with the baflle 16. A pair of flanges 78 onthe respective ends of the braille-16 provide for securing the baiiie tothe end wall of the chamber 44. The baffle 16 terminates a considerabledistance above the bottom of the chamber 44, said distance being greaterthan the space between the bafile 16 and the front wall of the chamber.The lower end of the baflle is curved forwardly as indicated by thereference character 66. The outlet conduit 48 extends into the chamber44 along the full length of the chamber at the high est pant of thechamber and back of the bafiie l6. Along the top of that portion of theconduit 43 tling begins at once.

which is within thecham'ben'is an orifice 82 through which air from thechamber enters the conduit. 4 The-cylindrical wall of the conduit at theedges of the orifice 82 is flanged upwardly and away fromthe-orifice-asindicated by the reference numeral 84 to prevent any dust deposited uponthe conduit from being swept into the orifice. In the front wall of thechamber M atthe lower portion thereof is 'a pair of'doors 86 which, maybe opened to provide access for cleaning out the deposit of dust. 3

The power for driving the tool shaft and the fan is derived from a motor88 secured upon a 'bracket'89 which in turn is pivotally mounted uponthe horizontal frame member I8. The bracket 89 is secured in any desiredposition of heightwise adjustment by an extensible rod 90, the upper andlower ends of which are pivotally connected to the bracket and the framemember I6 respectively. A belt 92 running under a pulley 94 on the motorshaft and over a pulley 96 on the shaft 28 drives the cleaning tools 26.On the motor shaft is a second pulley 98 which drives a belt I00. Fromthe pulley 98 the belt I is looped about a pulley I 02 on the shaft ofthe fan 50, thence about a pulley I04 0n the shaft 36, thence about apulley I06 close to the pulley I02 on the fan shaft and thence around apulley I08 close to the pulley I04 on the shaft 36. Between the pulleysI02 and I08 the belt makes a single loop around the pulley 98. The beltI00 is of'the type known .as a V-belt, having the cross-section of atruncated triangle, and it may be given an initial twist of 360, beforethe ends are joined, to avoid a twist after the belt is assembled uponthe pulleys. An advantage of the arrangement of the belt and pulleys asdescribed above resides in the fact that by providing two pulleys on theshaft 36 and also two pulleys on the fan shaft, the necessary belttraction can be obtained by the use of pulleys small enough to give adesirable speed ratio between the motor and the tool shaft.

In assembling the machine the bearing supports 31 are first adjusted tothe exact height to bring the several bufling tools into proper relationto their respective dust hoods, this adjustment being critical becauseof the close clearances heretofore mentioned. The motor supportingbracket 89 is then adjusted up or down by varying the length of the rod90 until the desired tension in the belt I00 has been obtained. Thebearing supports 29 may then be adjusted up or down to give the desiredtension in the belt 92.

When the machine is in operation, dust laden air will enter each of thevarious dust hoods between the tool and the associated throat 64. Assoon as this current of air has passed the tool its velocity willdiminish considerably in View of the large cross-section area of thepassageway leading down into the settling chamber. Because of this largecross-sectional area the movement of the air is relatively slow and theprocess of set- The hood therefore may be regarded as an upwardextension of the settling chamber. The velocity of the downwardly movingair within the chamber below the hoods will be slight because of therelatively great cross-sectional area of the forward portion of thechamber, that is, the portion which is forward of the bafile I6. Thegreater part of the dust entrained in the entering air will thus settleto the bottom of the chamber 44. The air in the forward portion of thechamber will then pass under the bafile I6, the space between the loweredge of the baffle and the bottom of the chamber being amply sufficientto avoid increasing the velocity of the air and thereby stirring up thedust which has been deposited. The outlet conduit 48 is positioned ashigh as possible above the level of the settling dust and the upwardcurrent of air in the portion of the chamber rear of the baffle '16 willmove with low speed to the orifice 82. The smallamount of duststillentrained in this air will be carried through the fan 50, and thenceinto the filter bag 54. The pressure developed byythe fan" 50need'be-little more than enough to vovercome the back pressure of thefilter and the friction in the conduits 48 and. 52' and through theorifice 82. Because of the relatively small amount of dust entrained inthe air a filter bag of moderate dimensions is sufficient to effectseparation of the dust to the required degree. Furthermore, because ofthe relatively small volume of air handled, and because of the fact thatthis air is delivered downwardly at low speed through the center of theplate 56, much of the dust entrained in the air entering the filter bagwill settle before reaching the walls of the bag. The amount of dust tobe screened as the air passes through the filter material is thereforesmall indeed. In view of these considerations, it becomes evident thatthe filter bag may be made much smaller than would otherwise beexpected. There is ample room within the frame structure between theupright members [0 and I2 not only for such a filter bag but also forthe motor 88 and the pulleys 94 and It is evident, from the abovedescription, that the apparatus operates by using a small volume of air,only enough to entrain the dust generated at the locality of operationand to carry this dust into the hoods, and by moving this air at arelatively low speed through the settling chamber and through thefilter, allowing the dust to settle of its own accord rather thanattempting to separate it forcibly from the air in which it isentrained. This principle of operation, as contrasted with centrifugalseparation, or with systems wherein high air velocity and abrupt changesof direction are relied upon, calls for a minimum expenditure of powerand at the same time affords an opportunity for the dust to settlenaturally. The apparatus described herein requires no power to create astrong suction at the hoods to prevent the escape of dust over the topof the tools, and it requires no power to speed up the air current forthe purpose of dust separation, but only enough power to overcome theback pressure of the filter and the friction of the air in passingthrough the apparatus. In avoiding high speed of the air current, anytendency to stir up dust already deposited is avoided, and the dust isgiven every opportunity to settle. The settling of the dust beginsimmediately upon the entry of the air into the hoods, and it continuesduring the slow descent of the air within the settling chamber.

Further settling takes place in the filter bag.

By far the greater proportion of dust is thus separated by settling, andonly a relatively small amount by filtration. Because of this fact, andbecause of the small volume of air handled, the filter, as has alreadybeen pointed out, may be relatively small. Furthermore, the small amountof air passing through the entire apparatus, and the utilization of theadditional space afforded by the dust hoods and filter bag for settling,enable the apparatus to be made more compact than might at first beexpected. The apparatus thus ofiers the two advantages of low powerconsumption and of compactness, both of which are of the highestimportance when the apparatus is to be used in connection with a shoerepair machine.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is: v

A dust settling chamber suitable for use in shoe repair machines,comprising a closed ,receptacle, a row of openings extending lengthwisealong the top of said receptacle for connection to individual dust hoodsfor the various tools of the machine, an exhaust conduit arrangedlengthwise in the upper portion of said receptacle and extending outsideof said receptacle, said conduit being substantially cylindrical andhaving a lengthwise. orifice along its top within the receptacle for theadmission of air from the receptacle, the wall of said conduit beingflanged upwardly and away from the orifice on each side of the orificeto prevent dust deposited on the conduit from being swept into theconduit, and a baflie within the vreceptacle and extending downwardlyfrom the top thereof between said conduit and said openings.

HERBERT J. WILLMOTT.

